215544961664 has 64 divisors (see below), whose sum is σ = 457455263040. Its totient is φ = 100810469376.

The previous prime is 215544961637. The next prime is 215544961691. The reversal of 215544961664 is 466169445512.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (215544961637) and next prime (215544961691).

It is a tau number, because it is divible by the number of its divisors (64).

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 50837 + ... + 658539.

It is an arithmetic number, because the mean of its divisors is an integer number (7147738485).

Almost surely, 2^215544961664 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 215544961664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (228727631520).

215544961664 is an abundant number, since it is smaller than the sum of its proper divisors (241910301376).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

215544961664 is a wasteful number, since it uses less digits than its factorization.

215544961664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 607897 (or 607885 counting only the distinct ones).

The product of its digits is 6220800, while the sum is 53.

The spelling of 215544961664 in words is "two hundred fifteen billion, five hundred forty-four million, nine hundred sixty-one thousand, six hundred sixty-four".